1. Field of the Invention
The invention relates to a swinging joint device, a walking assisting device, a conveying device, and a manipulator each of which performs cyclic swinging motion and includes a joint with variable rigidity. In addition, the invention relates to a walking-ability assisting device that assists user's walking or running.
2. Description of Related Art
As an example of a device that controls a joint that performs cyclic swinging motion, Japanese Patent Application Publication No. 2004-344304 (JP 2004-344304 A) discloses a walking assisting device that applies an assisting force to the lower limb (ranging from the hip joint to the foot) of a user. The walking assisting device includes a waist-part outfit attached so as to wind the waist part of a user, a joining bar extending from the lateral side of the hip joint to the lateral side of the knee joint of the user, a crus-part outfit extending from the lateral side of the knee joint to the calf of the user, a hip joint actuator attached to the joint bar at a position on the lateral side of the hip joint, and a knee joint actuator attached to the joint bar at a position on the lateral side of the knee joint. The hip joint actuator is attached to the joining portion of the waist-part outfit. The hip joint actuator on the lateral side of the hip joint swings the joining bar in a front-rear direction about the hip joint relative to the waist-part outfit. In addition, the knee joint actuator on the lateral side of the knee joint swings the crus-part outfit in the front-rear direction about the knee joint relative to the joining bar. The hip joint actuator and the knee joint actuator are electric motors, and power is supplied to the electric motors from a battery attached to the waist-part outfit.
In addition, Japanese Patent Application Publication No. 2012-125388 (JP 2012-125388 A) discloses a walking rehabilitation device that assists the swinging motion of the crus (ranging from the knee to the ankle) of a user. The walking rehabilitation device includes a controller disposed around the waist of a user, a femoral link extending from the lateral side of the hip joint to the lateral side of the knee joint of the user, crus links extending from both lateral sides of the knee joint to the ankle joint of the user, a motor disposed on the lateral side of the knee joint, and foot links extending from the ankle joint to the sole of the user. The motor is attached at the joining portion between the femoral link and the crus links and on the lateral side of the knee joint. The motor on the lateral side of the knee joint swings the crus links in the front-rear direction about the knee joint relative to the femoral link. Power is supplied to the motor from a battery included in the controller.
Moreover, Japanese Patent Application Publication No. 2013-236741 (JP 2013-236741 A) discloses a one-leg walking assisting machine that is attached to a leg in trouble of a user having one leg in good condition and the other leg in trouble, to assist the swinging motion of the leg in trouble. The one-leg walking assisting machine includes a waist attachment portion disposed on the lateral side of the waist of a user, a femoral link portion extending from the lateral side of the hip joint to the lateral side of the knee joint of the user, a crus link portion extending downward from the lateral side of the knee joint, a torque generation unit disposed on the lateral side of the hip joint, and a damper disposed on the lateral side of the knee joint. The torque generation unit is constituted by a cam and a compression spring, generates a torque when a leg in trouble swings backward with the swinging of a leg in good condition, assists the swinging of the leg in trouble using the generated torque, and requires no actuator such as an electric motor. In addition, the torque generation unit is configured such that an initial compression amount of the compression spring is adjustable and a magnitude of a generated torque is variable.
Both the walking assisting device described in JP 2004-344304 A and the walking rehabilitation device described in JP 2012-125388 A assist the walking motion of a lower limb or a part of the lower limb with the electric motors, but cannot assist the walking motion when power is not continuously supplied from the batteries. In addition, since a user who requires walking assistance does not afford to carry a large and heavy battery, it is assumed that the batteries used in the above devices are relatively small and lightweight. In addition, JP 2004-344304 A and JP 2012-125388 A do not describe any specific configuration that reduces the consumption power of the electric motors. Accordingly, it is assumed that the continuous operation times of the assisting devices described in JP 2004-344304 A and JP 2012-125388 A are relatively short.
The one-leg walking assisting machine described in JP 2013-236741 A generates a torque for swinging a leg through the cam and the compression spring without using an electric motor, and the continuous operation time of the assisting machine is longer than those of the assisting devices described in JP 2004-344304 A and JP 2012-125388 A. However, in accordance with a difference in body type (difference in inertia moment of a lower limb) of each user, a difference in swinging angle of a lower limb of each user, a user's physical condition, a difference in inclination of a walking place, and the like, it is required for a user to adjust the position of a determination portion provided on the compression spring of the torque generation unit with a tool such as a slotted screw driver and adjust an initial compression amount of the compression spring by hand. Therefore, such an operation becomes troublesome for the user.